Defence lawyer Pat Finucane was a thorn in the British establishment's side when alive, and the huge controversy surrounding his murder means he remains so, 13 years after his death.

Almost from the moment he died, his family was convinced that police officers and British soldiers colluded with the loyalist paramilitaries who carried out the shooting, in a conspiracy they suspect went to the heart of the corridors of power.

At the core of the case are accusations about the RUC special branch and the shadowy army force research unit, known as FRU, which it is claimed at best turned a blind eye to loyalist terrorism and at worst, actively encouraged the targeting of certain people.

On February 12 1989, the solicitor, his wife, Geraldine, and their three children, were eating dinner in their north Belfast home when members of Ulster Defence Association/Ulster Freedom Fighters loyalist paramilitary group broke down the front door with sledgehammers.

Two masked gunmen fired a total of 14 shots from a .38 revolver and a 9mm Browning automatic pistol, all of which hit Finucane. One bullet ricocheted off Geraldine's foot. The killers made their getaway in a stolen taxi, later abandoned on Woodvale Road.

The UDA/UFF said they killed the 38-year-old solicitor because he was a high-ranking officer in the IRA, but police at his inquest said they had no evidence to support that.

Several members of his family had strong republican links and he represented republicans in many high profile cases, but he had also acted for loyalists.

His brother, John, an IRA man, was killed on active service in a car crash in the Falls Road, Belfast, in 1972. Another brother successfully contested attempts to extradite him to Northern Ireland from the Irish Republic, while a third brother was the fiance of Mairead Farrell, one of the IRA trio shot dead by the SAS in Gibraltar in 1988.

Pat Finucane's best-known client was the IRA hunger striker, Bobby Sands. He also represented other IRA and INLA hunger strikers who died during the 1981 Maze prison protest, and the widow of Gervaise McKerr, one of three men shot dead by the RUC in a so-called "shoot-to-kill" incident in 1982.

Several UDA/UFF members were questioned at length in the weeks after Finucane's murder. No charges were brought, but concerns were multiplying in the family's minds. Three weeks before the shooting, Douglas Hogg, then a junior Home Office minister, had told the House of Commons that certain solicitors in Northern Ireland were unduly sympathetic to the IRA.

Indirect threats had been relayed to the solicitor through clients whom police had interrogated at the Castlereagh holding centre. An RUC officer was once reported to have told a client: "You will not be having Mr Finucane as a solicitor much longer."

Moreover, there were persistent allegations that detectives suggested the lawyer as a possible target to loyalists they were questioning in connection with terrorist offences. And on the night of the murder, the family said police roadblocks close to their home were lifted before the attack.

In 1992, UDA/army double agent Brian Nelson told a BBC Panorama programme that the UDA had asked him to compile a dossier on Finucane's movements. Nelson, who was jailed for 10 years for other terrorist offences but never charged in connection with Finucane, said he told his army handlers about the matter.

Sir John Stevens, the Metropolitan police commissioner, who had previously investigated other cases of alleged security force collusion with loyalists, started a second inquiry. The finger was pointed at FRU when his offices in Carrickfergus, Co Antrim, were mysteriously gutted by fire.

Throughout the 1990s, Amnesty International, the New York-based Lawyers Committee on Human Rights, and the Committee for the Administration of Justice were among the groups campaigning for an independent inquiry.

In 1998, Param Cumaraswamy, a United Nations Human Rights Commission expert on the independence of judges and lawyers, added his voice to inquiry lobby, but the RUC slammed his report as short of objectivity, accuracy and fairness.

Meanwhile, another former undercover soldier, known by the pseudonym Martin Ingram, broke ranks to claim that both FRU and special branch knew loyalists had tried to target Finucane on two previous occasions but he was not warned his life was in danger. Ingram also alleged that Tommy "Tucker" Little, head of the UDA brigade behind Finucane's murder, was a special branch informer.

Then in 1999, on its third inquiry, the Stevens team arrested a man who had been questioned about the murder in 1990. William Stobie, a self-confessed former UDA quartermaster and RUC informant, had told two journalists that he supplied the weapons for the Finucane murder without knowing who was to be killed.

Stobie insisted he told his RUC handlers almost a week before the murder that his UDA commander had asked him to get the guns for a "job" on a "top Provie", but he was amazed when police did nothing, either then or just before the killing, when he alerted them again, or later when he told them the principle murder weapon, a Browning pistol, had been moved from its hiding place.

Stobie claimed that special branch tried to set him up by tampering with UDA guns so he would be blamed and, on another occasion, framed him by planting guns in his home.

But during his trial for arms possession in 1990, he instructed his solicitor to tell the crown lawyer privately that he would tell all he knew about the Finucane case if he was found guilty. Minutes later, a police witness made an elementary mistake by referring to previous convictions and the judge declared a mistrial.

Mentally unfit

One of the two journalists to whom Stobie told his story was Ed Moloney, of the Dublin-based Sunday Tribune, who refused to hand over his notes to police. The other, Neil Mulholland, formerly with Belfast paper, Sunday Life, made a statement to the Stevens team. However, the case against Stobie collapsed in December 2001 when Mulholland was deemed mentally unfit to take the witness stand.

Less than a fortnight later, Stobie was shot dead outside his north Belfast flat, most probably by members of the UDA, exacting their final retribution for his disloyalty to their organisation.

Alan Simpson, the retired detective originally in charge of the Finucane case, was never told by his special branch colleagues that Stobie was an informer and now sees his situation as trying to catch the killers while having one hand tied behind his back.

Just after Stobie's murder, Ken Barrett, another UDA member alleged to be one of the gunmen who shot Finucane, and whom special branch also later recruited as an informer for a short time, fled to England, fearing he could be next.

Boasted

Another retired CID detective, Johnston "Jonty" Brown, told Ulster Television that Barrett had boasted about the murder in a surreptitiously taped conversation with him and a CID colleague in October 1991, during which a special branch officer was also present.

Brown said Barrett described details of the murder scene that only someone very close to the killing could have known, such as mockingly calling the victim "Fork Finucane" because he died holding a fork in his hand. But the tape which special branch eventually gave the Stevens inquiry team was recorded a week later and made no mention of the murder.

Barrett is believed to have given the Stevens team significant details of the murder, while under their protection in England. Another leading UDA member, William "Mo" Courtney, a close friend of Shankill UFF leader Johnny "Mad Dog" Adair, was arrested on suspicion of killing Finucane, but was freed without charge.

And in yet another twist, it recently emerged that police had recovered one of the murder weapons, the Browning pistol, originally stolen from an army barracks, but had amazingly given it back to the army, who replaced the barrel and slide, thus removing vital evidence in a case where the army itself is at the heart of the controversy.

To date, no one has been brought to justice in connection with the murder of Pat Finucane.

The Stevens team have tried to unravel the many seemingly inexplicable contradictions in the lead-up to the murder, the killing itself and its aftermath, and the government has now appointed an international judge, Peter Cory, from Canada, to re-examine the killing and five other murder inquiries where security force collusion is suspected.

But the Finucane family see both as delaying, cover-up tactics, and continue to battle for an independent, public inquiry as the only path to the truth in one of the most contentious and far-reaching cases of the past 30 years in Northern Ireland.